Root/drivers/virtio/virtio.c

1#include <linux/virtio.h>
2#include <linux/spinlock.h>
3#include <linux/virtio_config.h>
4#include <linux/module.h>
5#include <linux/idr.h>
6
7/* Unique numbering for virtio devices. */
8static DEFINE_IDA(virtio_index_ida);
9
10static ssize_t device_show(struct device *_d,
11               struct device_attribute *attr, char *buf)
12{
13    struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
14    return sprintf(buf, "0x%04x\n", dev->id.device);
15}
16static ssize_t vendor_show(struct device *_d,
17               struct device_attribute *attr, char *buf)
18{
19    struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
20    return sprintf(buf, "0x%04x\n", dev->id.vendor);
21}
22static ssize_t status_show(struct device *_d,
23               struct device_attribute *attr, char *buf)
24{
25    struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
26    return sprintf(buf, "0x%08x\n", dev->config->get_status(dev));
27}
28static ssize_t modalias_show(struct device *_d,
29                 struct device_attribute *attr, char *buf)
30{
31    struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
32
33    return sprintf(buf, "virtio:d%08Xv%08X\n",
34               dev->id.device, dev->id.vendor);
35}
36static ssize_t features_show(struct device *_d,
37                 struct device_attribute *attr, char *buf)
38{
39    struct virtio_device *dev = container_of(_d, struct virtio_device, dev);
40    unsigned int i;
41    ssize_t len = 0;
42
43    /* We actually represent this as a bitstring, as it could be
44     * arbitrary length in future. */
45    for (i = 0; i < ARRAY_SIZE(dev->features)*BITS_PER_LONG; i++)
46        len += sprintf(buf+len, "%c",
47                   test_bit(i, dev->features) ? '1' : '0');
48    len += sprintf(buf+len, "\n");
49    return len;
50}
51static struct device_attribute virtio_dev_attrs[] = {
52    __ATTR_RO(device),
53    __ATTR_RO(vendor),
54    __ATTR_RO(status),
55    __ATTR_RO(modalias),
56    __ATTR_RO(features),
57    __ATTR_NULL
58};
59
60static inline int virtio_id_match(const struct virtio_device *dev,
61                  const struct virtio_device_id *id)
62{
63    if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID)
64        return 0;
65
66    return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor == dev->id.vendor;
67}
68
69/* This looks through all the IDs a driver claims to support. If any of them
70 * match, we return 1 and the kernel will call virtio_dev_probe(). */
71static int virtio_dev_match(struct device *_dv, struct device_driver *_dr)
72{
73    unsigned int i;
74    struct virtio_device *dev = container_of(_dv,struct virtio_device,dev);
75    const struct virtio_device_id *ids;
76
77    ids = container_of(_dr, struct virtio_driver, driver)->id_table;
78    for (i = 0; ids[i].device; i++)
79        if (virtio_id_match(dev, &ids[i]))
80            return 1;
81    return 0;
82}
83
84static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env)
85{
86    struct virtio_device *dev = container_of(_dv,struct virtio_device,dev);
87
88    return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X",
89                  dev->id.device, dev->id.vendor);
90}
91
92static void add_status(struct virtio_device *dev, unsigned status)
93{
94    dev->config->set_status(dev, dev->config->get_status(dev) | status);
95}
96
97void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
98                     unsigned int fbit)
99{
100    unsigned int i;
101    struct virtio_driver *drv = container_of(vdev->dev.driver,
102                         struct virtio_driver, driver);
103
104    for (i = 0; i < drv->feature_table_size; i++)
105        if (drv->feature_table[i] == fbit)
106            return;
107    BUG();
108}
109EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);
110
111static int virtio_dev_probe(struct device *_d)
112{
113    int err, i;
114    struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
115    struct virtio_driver *drv = container_of(dev->dev.driver,
116                         struct virtio_driver, driver);
117    u32 device_features;
118
119    /* We have a driver! */
120    add_status(dev, VIRTIO_CONFIG_S_DRIVER);
121
122    /* Figure out what features the device supports. */
123    device_features = dev->config->get_features(dev);
124
125    /* Features supported by both device and driver into dev->features. */
126    memset(dev->features, 0, sizeof(dev->features));
127    for (i = 0; i < drv->feature_table_size; i++) {
128        unsigned int f = drv->feature_table[i];
129        BUG_ON(f >= 32);
130        if (device_features & (1 << f))
131            set_bit(f, dev->features);
132    }
133
134    /* Transport features always preserved to pass to finalize_features. */
135    for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
136        if (device_features & (1 << i))
137            set_bit(i, dev->features);
138
139    dev->config->finalize_features(dev);
140
141    err = drv->probe(dev);
142    if (err)
143        add_status(dev, VIRTIO_CONFIG_S_FAILED);
144    else {
145        add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
146        if (drv->scan)
147            drv->scan(dev);
148    }
149
150    return err;
151}
152
153static int virtio_dev_remove(struct device *_d)
154{
155    struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
156    struct virtio_driver *drv = container_of(dev->dev.driver,
157                         struct virtio_driver, driver);
158
159    drv->remove(dev);
160
161    /* Driver should have reset device. */
162    BUG_ON(dev->config->get_status(dev));
163
164    /* Acknowledge the device's existence again. */
165    add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
166    return 0;
167}
168
169static struct bus_type virtio_bus = {
170    .name = "virtio",
171    .match = virtio_dev_match,
172    .dev_attrs = virtio_dev_attrs,
173    .uevent = virtio_uevent,
174    .probe = virtio_dev_probe,
175    .remove = virtio_dev_remove,
176};
177
178int register_virtio_driver(struct virtio_driver *driver)
179{
180    /* Catch this early. */
181    BUG_ON(driver->feature_table_size && !driver->feature_table);
182    driver->driver.bus = &virtio_bus;
183    return driver_register(&driver->driver);
184}
185EXPORT_SYMBOL_GPL(register_virtio_driver);
186
187void unregister_virtio_driver(struct virtio_driver *driver)
188{
189    driver_unregister(&driver->driver);
190}
191EXPORT_SYMBOL_GPL(unregister_virtio_driver);
192
193int register_virtio_device(struct virtio_device *dev)
194{
195    int err;
196
197    dev->dev.bus = &virtio_bus;
198
199    /* Assign a unique device index and hence name. */
200    err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL);
201    if (err < 0)
202        goto out;
203
204    dev->index = err;
205    dev_set_name(&dev->dev, "virtio%u", dev->index);
206
207    /* We always start by resetting the device, in case a previous
208     * driver messed it up. This also tests that code path a little. */
209    dev->config->reset(dev);
210
211    /* Acknowledge that we've seen the device. */
212    add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
213
214    INIT_LIST_HEAD(&dev->vqs);
215
216    /* device_register() causes the bus infrastructure to look for a
217     * matching driver. */
218    err = device_register(&dev->dev);
219out:
220    if (err)
221        add_status(dev, VIRTIO_CONFIG_S_FAILED);
222    return err;
223}
224EXPORT_SYMBOL_GPL(register_virtio_device);
225
226void unregister_virtio_device(struct virtio_device *dev)
227{
228    device_unregister(&dev->dev);
229    ida_simple_remove(&virtio_index_ida, dev->index);
230}
231EXPORT_SYMBOL_GPL(unregister_virtio_device);
232
233static int virtio_init(void)
234{
235    if (bus_register(&virtio_bus) != 0)
236        panic("virtio bus registration failed");
237    return 0;
238}
239
240static void __exit virtio_exit(void)
241{
242    bus_unregister(&virtio_bus);
243}
244core_initcall(virtio_init);
245module_exit(virtio_exit);
246
247MODULE_LICENSE("GPL");
248

Archive Download this file

Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master

Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9



interactive